The present invention relates to an apparatus for towing vehicles and more particularly to an apparatus used with trucks and the like to provide an efficient means to tow a vehicle.
The first tow trucks had a large crane or boom arm mounted in the bed of a truck and used a hoist mechanism comprising various types of sling and chain arrangements associated with the arm which lifted one end of the disabled vehicle. For older styled and manufactured vehicles which used heavy gauge steel on bumpers, frame assemblies, and vehicle bodies, a crane arm and sling arrangement was satisfactory since the bumpers, frames and bodies of these older vehicles were strong enough to support a vehicle while it was being towed without causing appreciable damage to the vehicle. However, in recent years, car manufacturers have utilized lighter gauge steels and synthetic materials for bumpers, frames and bodies of various vehicles in order to lower manufacturing costs, raise fuel efficiency and provide shock-collapsible bumpers. These lighter gauge steels and synthetic materials markedly reduced the vehicle strength with the result that whenever one of these vehicles was towed with a conventional crane arm and sling arrangement, the vehicles were damaged at the bumpers, frames or even on the bodies near the fenders.
As a result of the above problems, manufacturers have recently redesigned tow trucks and associated apparatus used to tow vehicles so that instead of towing a vehicle by its frame and bumper, the vehicle is towed by its wheels. This has been accomplished through the use of wheel lifts comprising a suitable wheel engaging member which attaches to the front or rear of the wheels, and a suitable telescoping foot assembly which telescopes the wheel engaging member and also provides the lift to the wheel engaging member. While lifting the wheel engaging member, it is important to change the lift angle of the foot assembly from the horizontal when it is in its lowered position to an inclined position where the wheel engaging member is above the other end of the foot assembly in order to leave clearance between the foot assembly and the bumpers and flashings of those vehicles that are low-lying to the ground. Heretofore, prior art systems have used numerous moving parts with various pivoting points to change the lift angle of the foot assembly as it lifts the wheel engaging member and the secured vehicle. The complexity of such systems which use so many moving parts and pivot points creates problems of increased wear and maintenance periods and reduces overall efficiency while adding to the higher costs of manufacture.
It is accordingly an object of the present invention to provide an apparatus for towing vehicles and which overcomes the above noted deficiencies of the prior art.
It is a particular object of the present invention to provide an apparatus for towing vehicles which is readily adapted to be mounted to a truck chassis.
It is a more particular object of the present invention to provide an apparatus for towing vehicles which is of simple constructional design, and wherein the lifting mechanism automatically changes the angle of lift.